1. Field of the Invention
The present invention relates to a seatbelt device for securing an occupant to a seat with a seatbelt and ensuring the safety of such occupant upon a vehicle collision.
2. Related Art
A known seatbelt device comprises a collision detector for detecting a vehicle collision and outputting a collision signal, an airbag deploying in response to the collision signal, and a seatbelt device having a pretensioner for retracting a seatbelt in response to the collision signal.
However, according to this invention, a large amount of the seatbelt is protracted if, for example, an occupant is wearing clothes made of a thick material. Consequently, the amount of the seatbelt that needs to be wound would be large, because in order to effectively secure an occupant with a seatbelt device having a pretensioner, the seatbelt must have a tension above a prescribed value. If it takes time to effectively secure the occupant after an order for activating the pretensioner is given, the occupant is in the meantime displaced forward in the direction of the collision, entering the zone where the airbag is deploying. In other words, an occupant entering the airbag deployment zone while the airbag is deploying may contact the airbag and hit his/her head against the inflating airbag at the speed of its deployment.
Furthermore, winding of the seatbelt is delayed if the detection of the vehicle collision is delayed, whereby the occupant is displaced in the direction of the collision. Here also, the occupant may be displaced to the airbag deployment zone and hit his/her head against the airbag.
Furthermore, for the safety of the occupant, it is preferred that any vehicle employing a seatbelt device simply in combination with an airbag has its seatbelt device exchanged to a seatbelt device comprising a pretensioner. In such case, a traditional collision detector must also be exchanged to a collision detector capable of driving both an airbag device and a pretensioner, but this increases the number of parts which needs to be exchanged and is also costly.
A purpose of this invention is to provide a seatbelt device preventing the existence of the occupant""s body in the airbag deployment zone.
Another purpose of this invention is to provide a seatbelt device preventing the existence of the occupant""s body in the airbag deployment zone, easily replaced with a seatbelt device of a vehicle already equipped with an airbag device.
In order to accomplish the aforementioned purpose, a seatbelt device according to the present invention comprises; a seatbelt fastening detector for detecting that a tongue plate, through which a seatbelt for securing an occupant to a seat passes, has been engaged with a buckle; a collision predictor for predicting a collision of a vehicle and outputting a prediction signal before the collision; a collision detector for detecting the collision of the vehicle and outputting a collision detection signal; an airbag device deploying in response to the output of the collision detection signal; a first tension modifier and a second tension modifier capable of changing the tension of the seatbelt; and a controller for activating the first tension modifier in response to the prediction signal and enhancing the tension of the seatbelt, and activating the second tension modifier in response to the collision detection signal and further enhancing the tension of the seatbelt.
With such structure, if, for example, an occupant is wearing clothes made of a thick material, the first tension modifier is capable of winding before a vehicle collision any additional slack in the seatbelt caused by the thickness of the material, which needs to be wound by a second pretensioner serving as the second tension modifier. Therefore, a low-explosive powder pretensioner may complete the winding of the seatbelt before an inertia force displacing the occupant forward acts on the seatbelt. Thus, the occupant is prevented from being displaced in the direction of the collision further than a permitted range, and would not hit his/her head, etc. against a deploying airbag.
Furthermore, a seatbelt device according to the present invention comprises: a seatbelt fastening detector for detecting that a tongue plate, through which a seatbelt for securing an occupant to a seat passes, has been engaged with a buckle; a collision predictor for predicting a collision of a vehicle and outputting a prediction signal before the collision; a collision detector for detecting the collision of the vehicle and outputting a collision detection signal; an airbag device deploying in response to the output of the collision detection; an airbag activation detector for detecting the activation of the airbag device and outputting an airbag activation signal; a first tension modifier and a second tension modifier capable of changing the tension of the seatbelt; and a controller for activating the first tension modifier in response to the prediction signal and enhancing the tension of the seatbelt, and activating the second tension modifier in response to the collision detection signal and further enhancing the tension of the seatbelt.
With such structure, if a vehicle already equipped with an airbag device but its seatbelt device does not include a pretensioner has its seatbelt exchanged to a seatbelt device having a pretensioner, the traditional collision detector need not be exchanged to a collision detector capable of driving both the airbag and the pretensioner. Exchanging a traditional seatbelt device to a seatbelt device having a pretensioner is relatively easy, and can be done at a low cost.
Preferably, the first tension modifier is a device for winding or protracting the seatbelt by a motor power source, and the second tension modifier is a device for instantly retracting the seatbelt by a power source of powder combustion gas.
Preferably, the airbag activation detector outputs the airbag activation signal when a current supplied to an igniter for operating the airbag exceeds a prescribed current value, or when the temperature of the igniter exceeds a prescribed value.
Preferably, the airbag activation detector outputs the airbag activation signal when any one of currents supplied to a plurality of igniters for operating a plurality of airbags exceeds a prescribed current value, or when any one of the temperatures of the plurality of igniters exceeds a prescribed value.
Preferably, a seatbelt has a seatbelt retractor fixed to either a vehicle body or the seat for winding the seatbelt, and the first tension modifier and the second tension modifier are provided to the seatbelt retractor.
Preferably, a seatbelt device has a seatbelt retractor which is fixed to either a vehicle body or the seat for winding the seatbelt, and the first tension modifier is provided to the seatbelt retractor, and the second tension modifier is provided to the buckle portion.
Preferably, a seatbelt device has a seatbelt retractor which is fixed to either a vehicle body or the seat for winding the seatbelt, and the first tension modifier is provided to the buckle portion and the second tension modifier is provided to the seatbelt retractor, and the seatbelt retractor has a seatbelt locking mechanism for locking the protraction of the seatbelt when the first tension modifier is activated.
Preferably, the first tension modifier is provided to the seatbelt retractor winding one end of the seatbelt, and the second tension modifier is provided to the wrap belt fixing portion fixing the other end of the seatbelt to a vehicle body or the seat.
Preferably, the second tension modifier is provided to the seatbelt retractor winding one end of the seatbelt, the seatbelt retractor has a seatbelt locking mechanism for locking the protraction of the seatbelt when the first tension modifier is activated, and the first tension modifier is provided to the wrap belt fixing portion fixing the other end of the seatbelt to a vehicle body or the seat.
Preferably, the first tension modifier is provided to the buckle portion, and the second tension modifier is provided to a wrap belt fixing portion fixing the other end of the seatbelt to a vehicle body or the seat.
Preferably, the first tension modifier is provided to the wrap belt fixing portion fixing the other end of the seatbelt to a vehicle body or the seat, the second tension modifier is provided to a buckle portion, and the seatbelt retractor fixed to the vehicle body or the seat for winding-the seatbelt has a seatbelt locking mechanism for locking the protraction of the seatbelt in response to an ordering signal.
Preferably, the first tension modifier and the second tension modifier are provided to a wrap belt fixing portion fixing the other end of the seatbelt to a vehicle body or the seat, and the seatbelt retractor fixed to the vehicle body or the seat for winding the seatbelt has a seatbelt locking mechanism for locking the protraction of the seatbelt in response to an ordering signal,
Preferably, the seatbelt retractor is provided to the seat. The wrap belt fixing portion is preferably provided to the seat.